Endodontic files having a tapered flexible shaft with cutting edges thereon have been used for many years for enlarging a root canal. Heretofore, these instruments have generally been of the type illustrated in FIGS. 1 and 2 incorporating a handle 10 secured at one end of the shaft 12 opposite a somewhat pointed tip. Along a portion of the length of the shaft are the cutting edges or surfaces, normally spiral, serrated, or impregnated with sharp cutting material, used for enlarging and cleaning out the canal in the root of the tooth prior to filling it with inert material. The cutting or working portions of the prior art shafts have comprised a straight portion 14 illustrated in FIG. 1 or curved portion 16 shown in FIG. 2. An example of such an instrument is illustrated in U.S. Pat. No. 4,536,159. Although these prior art devices are suitable for their intended purpose, because of the relatively straight shaft, it is difficult to work on and enlarge specific areas along the root canal. It is to the improvement of such an endodontic root canal enlarging device that the present invention is directed.